In patent documents 1 and 2, there is disclosed the one-way pouring nozzle having a self-sealing function which can prevent an unintended air penetration into the flexible main package bag body, at every time before, during and after pouring of the material to be packaged, without regarding a time before and after forming of the tom-opening to the one-way pouring nozzle, in the case of pouring the material to be packaged from the package body, in which the material to be packaged in a liquid form or in a viscous form sometimes including powdery material, granular material and so on is filled and packaged in the package bag.
The one-way pouring nozzle disclosed in these patent documents is formed, by overlapping both ends of one folded thin and planar laminated film or by overlapping two thin and planar laminated films, each having sealant layers on both front and back surfaces and, by fusion-joining a peripheral portion of a formed pouring path without joining a base end side. This one-way pouring nozzle can pour a suitable amount of the liquid material to be packaged in the flexible main package bag body on the basis of a crush deformation and so on of the main package bag body by torn-removing a fusion-joined portion of a tip portion and opening the pouring path. At the same time, this one-way pouring nozzle can function to prevent an air penetration into the main package bag body by closing tightly an inner surface of the pouring path of the one-way pouring nozzle immediately under an existence of thin film of the material to be packaged due to a wetting on the basis of a capillary phenomenon and so on of the liquid material to be packaged, in the case of stopping a pouring based on a standing deformation of the main package bag body.
By the way, in the case of performing a subsequent pouring operation of the material to be packaged in the bag, the flexible main package bag body is tilted to direct the one-way pouring nozzle downward, so that the pouring path of the pouring nozzle is opened through the action of hydraulic head pressure and so on of the liquid material to be packaged, and the material to be packaged in the bag can be poured according to need.
Therefore, according to the package body comprising the one-way nozzle disclosed in the patent documents 1 and 2, the air penetration into the package bag can be sufficiently prevented at all times by sealing the package bag under degassing through in-liquid seal-packing and so on, and oxidation, pollution, putrefaction and so on of the material to be packaged in the bag can be surely prevented over the long term.
Patent Document 1: Japanese Patent Laid-Open Publication No. 2005-15029
Patent Document 2: Japanese Patent Laid-Open Publication No. 2005-59958